2015 年 74 巻 2 号 p. 73-77
Herein, we present a case report of the metastasis of a clear cell renal cell carcinoma (ccRCC) with an eosinophilic cell component to the skin of the submandibular region. An eosinophilic component has not been reported previously in the histological findings of ccRCC. The patient was a 74yearold man who had a painless papula in the right submandibular region. Six years earlier, he had undergone nephrectomy and had been diagnosed with stage 1 ccRCC (pT1a, N0, M0). At the current presentation, the dermis in the resected specimen was composed of a clear cell neoplasm with glycogen deposits. Upon immunohistochemical analysis, the clear cells were found to be positive for CD10 and vimentin. As these findings were similar to those from the nephrectomy specimen, the cutaneous lesion on the skin of the submandibular region was confirmed to be a lesion of the metastatic ccRCC. Even when a lowstage ccRCC with an eosinophilic cell component is diagnosed, critical pathological and clinical examinations are needed because distant metastases may occur to the head and neck region, as in this case. Furthermore, when a skin tumor is found in the head and neck region, metastatic RCC must be considered in the differential diagnosis.
